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cryptobyte: various API and documentation updates.

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Change-Id: I83236ecea0774d4ec49e978a391eb3ff5dabdeb6
Reviewed-on: https://go-review.googlesource.com/57810
Reviewed-by: Martin Kreichgauer <martinkr@google.com>
Reviewed-by: Adam Langley <agl@golang.org>
This commit is contained in:
Adam Langley
2017-09-12 17:47:39 +00:00
parent 88e95fbb56
commit 2bcb7b5baf
7 changed files with 438 additions and 99 deletions
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cryptobyte/example_test.go
+42 -8
View File
@@ -5,9 +5,11 @@
package cryptobyte_test
import (
"encoding/asn1"
"errors"
"fmt"
"golang.org/x/crypto/cryptobyte"
"golang.org/x/crypto/cryptobyte/asn1"
)
func ExampleString_lengthPrefixed() {
@@ -37,7 +39,7 @@ func ExampleString_lengthPrefixed() {
fmt.Printf("%#v\n", result)
}
func ExampleString_asn1() {
func ExampleString_aSN1() {
// This is an example of parsing ASN.1 data that looks like:
// Foo ::= SEQUENCE {
// version [6] INTEGER DEFAULT 0
@@ -51,12 +53,12 @@ func ExampleString_asn1() {
data, inner, versionBytes cryptobyte.String
haveVersion bool
)
if !input.ReadASN1(&inner, cryptobyte.Tag(asn1.TagSequence).Constructed()) ||
if !input.ReadASN1(&inner, asn1.SEQUENCE) ||
!input.Empty() ||
!inner.ReadOptionalASN1(&versionBytes, &haveVersion, cryptobyte.Tag(6).Constructed().ContextSpecific()) ||
!inner.ReadOptionalASN1(&versionBytes, &haveVersion, asn1.Tag(6).Constructed().ContextSpecific()) ||
(haveVersion && !versionBytes.ReadASN1Integer(&version)) ||
(haveVersion && !versionBytes.Empty()) ||
!inner.ReadASN1(&data, asn1.TagOctetString) ||
!inner.ReadASN1(&data, asn1.OCTET_STRING) ||
!inner.Empty() {
panic("bad format")
}
@@ -65,7 +67,7 @@ func ExampleString_asn1() {
fmt.Printf("haveVersion: %t, version: %d, data: %s\n", haveVersion, version, string(data))
}
func ExampleBuilder_asn1() {
func ExampleBuilder_aSN1() {
// This is an example of building ASN.1 data that looks like:
// Foo ::= SEQUENCE {
// version [6] INTEGER DEFAULT 0
@@ -77,9 +79,9 @@ func ExampleBuilder_asn1() {
const defaultVersion = 0
var b cryptobyte.Builder
b.AddASN1(cryptobyte.Tag(asn1.TagSequence).Constructed(), func(b *cryptobyte.Builder) {
b.AddASN1(asn1.SEQUENCE, func(b *cryptobyte.Builder) {
if version != defaultVersion {
b.AddASN1(cryptobyte.Tag(6).Constructed().ContextSpecific(), func(b *cryptobyte.Builder) {
b.AddASN1(asn1.Tag(6).Constructed().ContextSpecific(), func(b *cryptobyte.Builder) {
b.AddASN1Int64(version)
})
}
@@ -118,3 +120,35 @@ func ExampleBuilder_lengthPrefixed() {
// Output: 000c0568656c6c6f05776f726c64
fmt.Printf("%x\n", result)
}
func ExampleBuilder_lengthPrefixOverflow() {
// Writing more data that can be expressed by the length prefix results
// in an error from Bytes().
tooLarge := make([]byte, 256)
var b cryptobyte.Builder
b.AddUint8LengthPrefixed(func(b *cryptobyte.Builder) {
b.AddBytes(tooLarge)
})
result, err := b.Bytes()
fmt.Printf("len=%d err=%s\n", len(result), err)
// Output: len=0 err=cryptobyte: pending child length 256 exceeds 1-byte length prefix
}
func ExampleBuilderContinuation_errorHandling() {
var b cryptobyte.Builder
// Continuations that panic with a BuildError will cause Bytes to
// return the inner error.
b.AddUint16LengthPrefixed(func(b *cryptobyte.Builder) {
b.AddUint32(0)
panic(cryptobyte.BuildError{Err: errors.New("example error")})
})
result, err := b.Bytes()
fmt.Printf("len=%d err=%s\n", len(result), err)
// Output: len=0 err=example error
}